Spark plug



Aug. 26, 1941. c. E. MEYER SPARK PLUG Filed Feb. 24, 1940 Patented Aug. 26, 1941 UNITED" STATES PA ENT! foal-"ice 1jj1 2,254,082 SPARK PLUG Charles Eugene Meyer, Nenilly-snr-Seine, France, vassignor to Socit de Construction dAppareils Meaniques & Eleotriques pour Automobiles S. C. A. M. E. A., Neuilly-sur-Scinc, France, a

company of France Application February 24, 1940; Serial No. 320.53

In Luxemburg March 18, 1939 16 Claims.

The present invention relates to spark plugs for automobile vehicles.

Two of the chief elements of a spark plug of thislrind, to wit the insulating portion and the central electrode, respectively, are usually assembled together by means of a special cement.

This method of assembly involves serious drawbacks: Either it is not fluidtight to gases, which are thus allowed to leak out through the plug, or it lacks elasticity-in which case, the insulating portionof the plug may burst under the effect of the expansion of the central electrode.

There is also another way of assembling the insulating-portion and the central electrode, which consists inpacking the space between the electrode and the walls of the housing provided in said insulating portion for said electrode with a powdery matter such as talcum or crushed steatite, or any other suitable body.

last mentioned method ensures good results as to the strength and fluidtightness of the assembly, but it is disadvantageous from the point of view of the cooling of the electrode, because thetightly packed-matter that is used is a bad conductor of heat and operates as heat insulating means around the electrode. I

The object of the present invention is to provide a spark plug which obviates the above men tioned drawbacks, and in particular a method of assembling the insulating portion of a spark plug with its central electrode which permits f obtaining a perfect fluidtight connection irrespective of the variations of temperature to which the plug is subjected on an internal combustion engine, and a better, outflow of the heat of the electrode toward the electricity insulating portion.

According to an essential feature of the present invention, the spark plug is made in "the following manner:

- I interpose, between the central electrode, eventually either above or below an enlarged portion I exert on the whole of the ringi the andthe washer, a very high axial pressur so aslto central electrode.

crush them. 4

In this way, I obtain a perfectly iluidiight connection between the insulating portion and the The crushing of the washer serves to prevent any possibility of inflow of the powdery matter into the punching tool which compresses the whole. Also it fixes the elements in position along the rod, and it permits the outflow of heat from the electrode.

The paste above referredto may advantageous ly be made of the following composition: 7

Per cent Talum--- 75 Clay- I 20 Titanium oxide 5 This composition of matter is caused to pass through a tubular drawing tool to form a tube. This tube is cut into portions and dried before or after this cutting.

Other features of the present invention will result from the following detailed description of some specific embodiments thereof.

A preferred embodiment of the present inven 'tion will be hereinafter described with reference to the accompanying drawing given merely by way of example, and in which- Fig. 1 is an axial sectional view of the electric insulating portion. of a spark plug in which are; engaged the electrode rod and the inner'ring made of a malleable metal;

thereof,"and the housing provided in the electric insulating sheath for said electrode, a malleable matter which is a good conductor of heat.--.

- Advantageously, for this purpose, according to I the invention, I deform, by means of a high pressure, aring constituted of said malleable material, for instance a metal, such as copper, aluminium, etc., surrounding the electrode rod.

I I place on-said rod,.adjacent to the ring, a tube made of a paste of talcum or steatite and an agglomerating body, which paste has been previously dried.

I engage on said rod, next to said tube, a ring or washer of a malleable material or metal, and

Fig. 2 is a view similar to Fig. 1, showing the same elements after the malleable metal ring has been crushed;

Fig. 3 is a similar view showing the sameparts after the steatite tube and the upper ring have been engaged on the electrode rod; 1

Fig. 4 is a similar view showing the parts of Elbe spark plug after the electrode has been finally tted:

Fig. 5 is a detail view showing in elevationpartly in section, a portion of the tube of isteatite paste.

In the spark plug illustrated by the drawing, a designates the, electric insulating body of the plug and b is the central electrode. The electric insulating body is provided, over its whole height,

with a conduit or housing a adapted to accommo'date said central electrode. .The latter includes a rod b having a part I: of enlarged section resting, upon the conical (or curved) hearing or bottom of housing a (Fig. 1). 0n the rod b of the electrode, 1- place a ring c of a malleable metal, in the manner illustrated by Fig. 1.

This'ring c is subjected to the action of a high pressure by means of a tubular punching tool d. This pressure may, for instance, be obtained through the action of the piston of a small air pump acting on the upper end of the above mentioned punching tool d. Ring is deformed as shown by Fig. 2 and, in this state, it ensures an intimate contact between the portion b of the arately by Fig. 5. The diameter of this tube e is slightly smaller than the diameter of the housing a provided in body a, so as to permit of easily introducing this tube into the insulating body, as shown by Fig. 3. On the top-of this tube e, I place a ring or washer f of a malleable matter or metal (Fig. 3).

The whole is then subjected to a very high axial pressure by means of tool d acting on washer f, in a manner similar to that above referred to for the crushing of ring 0. This pressure produces the crushing of tube e and of Washer or ring I, thus ensuring a perfect contact between the electric insulating body a and the central electrode 1), and also an absolute fiuidtightness. This state is illustrated by Fig. 4.

The insulating body :1 obtained as shown by Fig. 4, and having its electrode b satisfactorily fitted therein is then mounted in its metallic cap in the usual manner.

Of course, the tube of matter e is not necessarily made of a: single element. It might for instance be made of a plurality of superposed cylindrical elements, which would be subsequently agglomerated together in a perfectly intimate manner by the crushing action performed by tool d or any other means so that in the final state illustrated by Fig. 4 the whole of the matter is tightly packed in a uniform manner around rod b and between the end metal rings 0 and f.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eflicient embodiments of the present invention, it should -be well understood that I do not wish to be limited thereto as there might -be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope -of the appended claims.

What I claim is: g

1. A method of securing in the shouldered bore of the insulating core of a spark plug a central electrode smaller in cross section than the larger portion of the bore, which comprises inserting said electrode into the bore, engaging on said electrode a ring of malleable, heat-conducting matter, subjecting said ring to a high compression so as to deform it against the shoulder and the side wall of the larger portion of said bore, placing next to said ring at least one tube of agglomerated powdery material, and successively, a washer of malleable, heat-conducting matter, and, strongly compressing the whole in the axial direction so as to deform the elements above mentioned and to .apply them tightly against the walls of the electrode and of the larger portion of the bore.

2. A method of securing in the shouldered bore of the insulating core of a spark plug a central electrode smaller in cross section than the larger portion of the bore, which comprises inserting said electrode into the bore, engaging on said electrode a ring of malleable metal, subjecting said ring to a high compression so as to deform it against the shoulder and the side wall of the larger portion of said bore. placing next to said ring at least one tube of agglomerated powdery material, and. successively, a washer of malleable metal, and strongly compressing the whole in the axial direction so as to deform the elements above mentioned and to apply them .tightly against the walls of the electrode and of the larger portion of the bore.

3. A method of securing in the shouldered bore of the insulating core of a spark plug a central electrode smaller in cross section than the larger portion of the bore, which comprises inserting said electrode into the bore, engaging on said electrode a ring of malleable metal, subjecting said ring to a high compression so as to deform it against the shoulder and theside wall of the larger portion of said bore, placing next to said ring at least one tube of agglomerated mixture comprising talcum and clay, and, successively, a washer of malleable metal, and strongly compressing the whole in the axial direction so as to deform the elements above mentioned and to apply them tightly against the walls of the electrode and of the larger portion of the bore.

4. A method of securing in the shouldered bore of the insulating core of a spark plug'a central electrode smaller in cross section than the larger portion of the bore, which comprises inserting .said electrode into the bore, engaging on said electrode a ring of malleable metal, subjecting said ring to a high compression so as to deform it against the shoulder and the side wall of the larger portion of said bore, placing'next to said ring at least one tube of agglomerated mixture comprising steatite and clay, and, successively, a washer of malleable metal, and strongly compressing the whole in the axial direction so as to deform the elements above mentioned and 'to apply them tightly against the walls of the electrode and of the larger portion of the bore.

5. A method of securing in the shouldered bore of the insulating core of a spark plug a central electrode smaller in cross section than the larger portion of the bore and having a ring around it and integral with it, whichcomprises inserting said electrode into the bore, so that said integral ring rests on the shoulder of said bore, engaging on said electrode a ring of malleable heat-conducting matter, subjecting said malleable ring to a high compression so as to deform it against the ring integral with the electrode and against the shoulder and the side wall of the larger portion of said bore, placing next to said ring at least one tube of agglomerated powdery material, and, successively, a washer of malleable, heat-conducting matter, and strongly compressing the whole in the axial direction so as to deform the elements above mentioned and to apply them tightly against the walls of the electrode and of the larger portion of the bore.

6. A method of securing in the shouldered bore of the insulating core of a spark plug a central electrode smaller in cross section than the larger portion of the bore and having a ring around it and integral with it, which comprises inserting said electrode into the bore, so that said integral ring rests on the shoulder of said bore, engaging i and next to said ring at least one ated mixture comprising steatite and clay,

side wall of the larger portion 'of said bore, placing 1 next to said ring at least one tube of agglomerated powdery material, and, successively, a washer of malleable metal, and strongly compressing the whole in the axial direction so as to deform I theelements above mentioned and to apply them tightly against the walls of the electrode and of the larger portion of the bore.

7. A method of securing in the shouldered bore of theinsulating core of a spark plug a central electrode smaller in cross section than the larger portion of the bore and having a ring around it and integral with it, which comprises inserting said electrode into the bore, so that said integral ring rests on the shoulder of said bore, engaging on said electrode a ring of malleable metal, subjecting said malleable ring to a high compression so as to deform it against the ring integral with the electrode and against the shoulder and the side wall of the larger portion of said bore, placa ing next to said ring at least one tube of agglomerated mixture comprising talcum and clay, and, successively, a" washer of malleable metal, and strongly compressing direction so as to deform the elements above mentioned and to apply them. tightly against the the whole in the axial walls of the electrode and of the larger portion 1 oi the bore.

8. A method of securing in the shouldered bore of the insulating'core of a spark plug a central electrode smaller in cross section than the larger portion of the bore andhaving aring around'it integral ,with it, which comprises inserting said electrode into the bore, so that said integral ring rests on the shoulder of said bore, engaging on said electrode a ring of malleable metal, subjecting said malleable ring to a high compression so asto deform it against the ring integral with the electrode and against the shoulder and the side portion oi. said bore, placing tube of agglomerand,

wall of the larger the whole in the axial dithe elements above-menpressed against said ring between said electrode and the wall of the larger portion of said bore,

over a portion of the length of said electrode, and a second ring of malleable, heat-conducting matter tightly applied against said tubular layer,

between the electrode and the wall of the bore.

10. A spark plug in accordance with claim 9, and in which said rings are of a malleable metal.

'11. A spark plug in accordance with claim 9, and in which said agglomerated powdery material is a mixture comprising talcum and clay.

12. A sparkplug in accordance with claim 9, and in which said agglomerated powdery material is a mixture comprising steatite and clay.

13. A spark plug comprising aninsulating core having a central shouldered bore therethrough, an electrode mounted in said bore and having a ring around it and integral with it, a first ring of malleable, heat-conducting matter surrounding said electrode and tightly applied against its side wall and said integral ring and against the wall of the bore, a tubular layer of agglomerated powdery material compressed against said ring between said electrode and the wall of the larger portion of said bore, over a portion oi the length 14. A spark plug inaccordance with claim 13,

and in which said rings are of a malleable metal. 15. A spark plug in accordance with claim 13, and in which said agglomerated powdery material is a mixture comprising talcum and clay.

16. A spark plug in accordance with claim 13, and in which said agglomerated powdery material is amixture comprising steatite and clay.

cHARLEs EUGENE ME ER. 

